McMahon charges that Murphy broke House rules by obtaining a home equity loan from a bank he once represented as a lawyer, Politico reports. In a Sept. 7 letter to the OCE, McMahon’s campaign manager Corry Bliss requested a probe of whether Murphy “has accepted a prohibited gift and used his official position to secure himself personal and political financial benefit.”

For months, Democrats assumed Murphy had lock on the Senate seat, but Real Clear Politics now rates the race as a toss-up. The latest major poll, conducted by Quinnipiac Aug. 22-26, showed McMahon with a 3 percentage point lead. The two are fighting for the seat being vacated by retiring independent Joe Lieberman.

To be sure, McMahon’s complaint will likely generate little more than headlines before the Nov. 6 election. That’s because the OCE’s rules prohibit it from referring a case to the House Ethics Committee — which is the body that acts on such charges — within 60 days of balloting.

Not surprisingly, both Murphy and Webster Bank, which provided him with the home equity line under question and a mortgage, deny doing anything wrong.

In March 2007, just two months after being sworn in for his first term in the House, Murphy was sued for defaulting on the $180,000 home mortgage that originated with Webster. He represented himself in the case, which was later dropped. Then in July 2008, Murphy received the $43,000 home equity line from Webster. Congressmen are forbidden from receiving any benefit that isn’t “generally available” to the public.